Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"gas hold-up"”.
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GAS HOLD-UP MEASUREMENTS IN 0.3 m DIAMETER BUBBLE COLUMN: EFFECT OF ELECTROLYTES
… work reports the axial, radial and temporal gas hold-up profiles in a 0.3 m diameter batch bubble column using a pair of Wire Mesh Sensors and six pressure transducers.</p>
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Application of electrical resistance tomography in evaluating the influence of nozzle design on the gas hold-up in boiling bubble column reactors
… of high rates of heat and mass transfer coupled with low operating and maintenance costs. The complex hydrodynamics brought about by the multiphase nature of such systems offer significant challenges in modelling, analysis and operation, thus making experimental measurement of system …
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Rheological effects on gas dispersion in a pilot scale mechanical flotation cell
… in mechanical flotation cells, where effective gas dispersion is a primary requirement for particle-bubble contacting. Due to the mineralogical complexity of ores, it is required that particles be ground even finer to liberate valuable minerals. Mining operations tend to run flotation circuits …
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Gas-liquid simulation of an airlift bubble column reactor
… on industries such as bioprocess industries. The gas-liquid of two-phase fluid flow system has been carried out to investigate the hydrodynamics parameter. An Eulerian-Eulerian approach was used to model air as the dispersed phase within a continuous phase of water using the commercial software …
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Behaviour of Bubble Columns with Two and Three Phases
… operating conditions and phase properties on the gas hold-up, flow regimes, bubble dynamics and mixing in two- and three-phase systems. Complex two- and three-phase systems were also tested. Air, water and a variety of solid particles were used as the gas, liquid and solid phases respectively. …
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Vibrations for improving multiphase contact
… contacting systems: a bubble column for gas-liquid contacting (physical absorption) and a Piston Oscillating Monolith Reactor (POMR) for gas-liquid-solid contacting (catalytic reactions). In a bubble column reactor, enhancements of mass transfer coefficient and gas hold up were …
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Development of a photobioreactor for the cultivation of the freshwater microalga Haematococcus pluvialis
… as a aquaculture pigment, and as a human health supplement. Currently the majority of astaxanthin used in aquaculture is synthetic. However recent advances in algal mass culture technology and growing consumer awareness about the origins of foodstuffs mean that the use of H. pluvialis for the …
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Agitation, mixing and mass transfer in simulated high viscosity fermentation broths
Gas-liquid mass transfer, agitator power consumption, rheology, gas-liquid mixing and gas hold-up have been studied in an agitated, sparged vessel of diameter, T = 0.3 m, with a liquid capacity of 0.02 m\(^3\), unaerated liquid height = 0.3 m. The solutions of sodium carboxymethylcellulose used …
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A Study of Rhamnolipid Microbubble Dispersion for Bioremediation Applications
… and the mechanism and factors that impact upon the effectiveness of the dispersion for improving bioremediation efficiency, with a specific focus on the use of microbubble dispersion as a carrier for contaminant-degrading bacteria within a bioremediation scenario. Microbubble dispersion is …
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Hydrodynamics and Mass Transfer in Bubble Columns
… In spite of their widespread usage, the scale-up of bubble columns remains an ongoing challenge. Various scale-up approaches, based on concepts ranging from ideal mixing to complex 3-D multiphase CFD models, have been used for assessing the effect of column size and gas and liquid flow rates on …
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Oxygen Mass-Transfer in Tower Fermenters
… of unsteady-state experiments. The effects of gas flow-rate, nutrient concentration, antifoams and microbial concentration on mass—transfer have been studied in detail: superficial air velocity and the presence of anti-foams are shown to be the most important factors. Measurements with the …
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Process development and scale-up from shake flask to fermenter of suspended and immobilized aerobic microorganisms
… with the standard measuring methods, exhaust gas analysis and respirometry. A simple and inexpensive shake flask screening method to perform immobilization studies with solid supports is introduced. This method is applied to study the adhesion of dormant and growing cells to ceramic and glass …
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Numerical simulation of bubble columns by integration of bubble cell model into the population balance framework
… challenges pertaining to their design, scale-up and optimization. These challenges are due to the hydrodynamics being complex to simulate. In most cases the current models fail to capture the dynamic features of a multiphase flow. In addition, since most of the developed models are empirical, …
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Multiphase CFD modelling of stirred tanks
… led to the study of fluid flow within the tanks upon agitation; so that a better understanding of the phenomena can help in the optimisation of the tanks. In the recent years, efforts have been made towards the development of predictive methods using computational fluid dynamics (CFD). Among the …
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Flotation in a novel oscillatory baffled column
… cell design in that bubble generation is decoupled from the power input. This allows the hydrodynamic environment to be optimised for effective particlebubble contacting. The design also incorporates a novel mechanism of agitation which provides a more even distribution of shear rate than …
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Void fraction measurements in large (0.3 m) diameter bubble column using Wire Mesh Sensor and Pressure transducers- Effect of sparger
… Experiments were performed for seven superficial gas velocities, to cover both Homogenous and Heterogenous flows. Two different spargers (point sparger and four arm spargers) were used to study the effect of the sparger design on the hydrodynamics. The measurement uncertainty of the WMS …